Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint. The description adds useful behavioral context beyond that: it is a preview that returns network choice, price, eligibility, and arrival window, and it has no acceptance or booking side effect. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two tight sentences with no filler. The read-only nature is front-loaded, the return information is compactly listed, and the closing caveat about not being required for booking earns its place. Well-structured and efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description does provide a useful high-level summary of the response contents and the non-committal pre-booking context. However, it leaves some gaps for an agent: the policy enum semantics, optional parcel constraints, and the meaning of the pinned robomart_version are not addressed, so the description is strong but not fully complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, and the description does not compensate by explaining the parameters. It never clarifies the meaning of the parcel dimensions, the policy enum values ('allow_roaming', 'on_network_only'), or robomart_version. Pickup and dropoff addresses are inferable from context, but the policy parameter is central to the network decision and is left entirely to the schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: a read-only route preview. It enumerates the concrete outputs (network, flat price, eligibility, arrival window) and clearly separates itself from fulfillment siblings like book_delivery and track_delivery by framing it as pre-booking and non-committal.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear usage context: use this before booking as a low-risk preview, and explicitly says there is 'nothing to accept' and it is 'never required before booking.' It does not name sibling alternatives or state when not to use it (e.g., for tracking or cancellation), so it stops short of full explicit routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.